Development of Electric Motor for Electric Motorcycle for Business Use 2011-32-0560
A new DC brushless motor, which has an almost equivalent driving
performance to a 50 cm₃ scooter engine, has been developed to be
used in a new electric motorcycle for business. The traction motor
is compact enough to be mounted close to the driveshaft of the
transmission, which helps reduce friction in the drive train.
Consequently, in the downsized motor, by mounting the drive
train unit with the PDU (Power Drive Unit) on the wheel side by
applying reduction gears, it enables the reduction of maximum motor
torque requirement. It also enables other parts of the drive system
to be integrated into one unit. In this motor, IPM (Interior
Permanent Magnet) structure has been implemented to cope with the
high rotation of the motor, and the concentrated winding stator
coil has been implemented for downsizing. As for the rotor, the
magnets were placed in sections and the yoke shapes were improved
to achieve higher rotation speeds that provide the higher power.
The motor performances with the maximum power of 2.8 kW, the
maximum torque of 11 Nm, the practical efficiency of 75% or more,
and the maximum motor speed of 9000 r/min or more, have been
achieved, which have satisfied the maximum specifications required
from the drive train unit of the motorcycle.